This invention generally relates to refiners for lignocellulosic materials, and more specifically to a method and system for changing refiner plate segments in such a refiner.
Refiner plate segments are a critical component of the refining equipment. They are also a wear part that requires changing on a regular basis, in order to maintain the refining performance over time. A typical circle of refiner plates is composed of anywhere between 3 and 24 equally-sized segments, which together form a circle. At most, if not all, refiner plate changes, all segments are removed; the mounting surfaces (that is, the surfaces of the rotor and stator disk) are cleaned; and the new refiner segments are installed one-by-one, including shimming them to keep equal spacing and torquing the attachment bolts properly.
Refiners usually have 2 circles of plates running opposite each other, or in case of Twin refiners, they have 4 circles of plates (including a double-sided rotor). The refiner may be made with one rotor facing one stator (a rotating disk facing a stationary disk), or two opposing counter-rotating rotors.
Currently segmented refiner plates are either mounted individually to the rotor or stator surfaces in the refiner or fixed to separate plate holders that are of sufficient thickness to contain the full length of the required segment attachment bolts. These separate plate holders are then attached to the grinding machine as a complete assembly after the segments are fixed to the plate holder.
Converting machines not originally equipped with these thick plate holders may typically require a major rebuild of the machine as the plate holder thickness must be removed from the rotor and stator surfaces to allow the added thickness of the plate holders. This is a time consuming and costly process.
In certain aspects, the present invention may provide the labor saving and ergonomic benefits of the thick plate holder concept without the requirement for an extensive machine rebuild and the associated cost. Additional labor savings may be realized at the mill site when the face mounted carrying and installation fixture is supplied as a complete assembly with the segments precisely positioned for proper balancing required to minimize grinding machine rotational vibration. The assembly may then be ready for installation into the grinding machine as a single unit with significantly less mill site assembly labor and cost.